How Much Sleep Do I Need?

You know sleep is important. But clocking a full eight hours every night seems like a luxury. How much do you really need?

“Two of the main factors that determine the amount of sleep you need are genetics and age,” says Michelle Drerup, PsyD, a psychologist and sleep disorder specialist. Here’s how to find out if you’re hitting your target — or whether your bedtime needs a makeover.

How many hours of sleep do I need?

Babies need a lot of sleep. As kids grow, their sleep needs decrease. “By adulthood, most healthy people need 7 to 8.5 hours,” Dr. Drerup says.

Here’s how much kids and adults need, on average according to the CDC:

Shortchanging your sleep long-term can lead to a host of problems, including:

• Diabetes.
• Depression.
• Heart problems.
• High blood pressure.
• Lowered immunity.
• Obesity.

Sleep myths, busted

Though sleep needs vary depending on your genes, most adults fall in the seven-to-nine-hour range. If you think you thrive on less, you may want to reconsider.

“There are people who are short sleepers, but it’s pretty rare,” Dr. Drerup notes. “We’re not very good judges of how sleep loss affects us, and most people who think they do well on little sleep would probably function better with a little more.”

One common misconception is that older adults don’t need as much sleep as they did in middle age. Older adults should still aim for at least seven hours, Drerup says.

“Older adults have different sleep patterns. They tend to sleep more lightly and may wake earlier in the morning,” she says. “But you still need the same amount of sleep over 24 hours, so if you’re sleeping less at night, you might need a nap during the day.”

Sleep sleuth: Find out how much you need

What’s the magic number of hours you should be sleeping? Dr. Drerup offers two strategies for finding out how rested you really are.

• Keep a sleep diary: “Track the time you go to bed and wake up and look for patterns. How do you feel when you wake up, in the afternoon and at the end of the day? Do you have a midafternoon slump or feel like you need an extra cup of coffee?” she says. “If so, you may not be meeting your sleep needs.”
• Take a sleep vacation: “If you have the flexibility, pick a consistent bedtime and get up without an alarm for a week or two,” she suggests. If you’re sleep-deprived, you’ll probably sleep a lot longer the first few days. But after three or four days, the amount of sleep you get each night should be close to what your body needs naturally.

How long is a sleep cycle?

An average sleep cycle lasts about 90 minutes. Ideally, you want to get five or six of those cycles each night to feel fresh and rested.

You might not have a lot of choice about what time the alarm clock rings in the morning. But you may be able to tweak your bedtime. Figure out how many hours you want to be slumbering, then add on an extra 15 minutes to give yourself time to fall asleep. For example:

What Time Should I Wake Up and Go to Bed?

Here are some targets for getting seven or eight hours of sleep.

Tips for bedtime success

Dr. Drerup offers these tips for sleep success:

• Wind down: Before bedtime, wind down by turning off electronic devices, turning down lights and doing calming activities (like taking a warm bath, reading, and relaxation) that will help your body get sleepy.
• Go slow: If you’re used to staying up until 2 a.m., you aren’t likely to fall asleep at 11 p.m. Start by shifting your bedtime back by 15 or 20 minutes. After a couple of days, turn it back another 20.
• Be consistent: If you cut sleep short during the week, you won’t be able to fully make up that sleep debt on weekends. Instead, aim to go to bed and wake up close to the same time each day.
• Be flexible: “You won’t be perfectly consistent every night,” she says. “But if you’re within an hour of your ideal sleep target, that’s a good goal.”

When you’re feeling regularly well-rested and bright-eyed after a solid night’s sleep, you’ll wonder why you ever tried to get by with less.